College of Agronomy, Hunan Agricultural University, Changsha, Hunan 410128, China; State Key Laboratory of Hybrid Rice, Hunan Hybrid Rice Research Center, Changsha, Hunan 410125, China.
State Key Laboratory of Hybrid Rice, Hunan Hybrid Rice Research Center, Changsha, Hunan 410125, China.
Ecotoxicol Environ Saf. 2022 Jul 15;240:113683. doi: 10.1016/j.ecoenv.2022.113683. Epub 2022 May 30.
In order to identify the key transport process that determines the Cd concentration in brown rice, this study used 21 hybrid rice varieties as experimental materials and conducted field experiments in Qiyang (cadmium-contaminated site) and Yongding (low-cadmium site). Cd concentrations in 8 organs were measured, and bioconcentration factors and transfer factor were further calculated. The results showed that the Cd concentrations of the organs related to the xylem transport were as follows: root > node > stem > leaf sheath > leaf. In the phloem, the Cd concentrations were as follows: rachis > brown rice > rice husk. And the results of the correlation analysis found that Cd concentration between brown rice and root showed a significant positive correlation in Cd-contaminated site, but no significant correlation in low-cadmium site. Meanwhile, at both experimental sites, the Cd concentration of brown rice showed the most significant correlation with the phloem transfer factor from leaf and leaf sheath to brown rice. Principal Component Analysis (PCA) and stepwise regression analysis likewise found that Cd concentration in leaf and leaf sheath and their phloem transport of Cd to brown rice were significantly and positively correlated with Cd concentration in brown rice. The above results showed that the transport of leaf and leaf sheath to brown rice was a key process, and played a more important role in the accumulation of cadmium in brown rice than in root.
为了确定决定糙米中 Cd 浓度的关键传输过程，本研究以 21 个杂交水稻品种为实验材料，在祁阳（镉污染区）和永定（低镉区）进行了田间试验。测量了 8 个器官中的 Cd 浓度，进一步计算了生物浓缩因子和转移因子。结果表明，与木质部运输有关的器官 Cd 浓度如下：根＞节＞茎＞叶鞘＞叶。在韧皮部中，Cd 浓度如下：穗轴＞糙米＞稻壳。相关性分析结果表明，在 Cd 污染区糙米与根之间的 Cd 浓度呈显著正相关，但在低镉区无显著相关性。同时，在两个实验点，糙米的 Cd 浓度与叶片和叶鞘中韧皮部向糙米转移的转移因子呈最显著相关。主成分分析（PCA）和逐步回归分析同样发现，叶片和叶鞘中的 Cd 浓度及其向糙米的韧皮部 Cd 运输与糙米中的 Cd 浓度呈显著正相关。上述结果表明，叶片和叶鞘向糙米的运输是一个关键过程，在糙米中 Cd 的积累中比在根中起着更重要的作用。
